4.8:Mean, Median, Mode & Range Measures of Central Tendency

Definition Mean Means Average

How to Find the Mean of a Group of Numbers Step 1 – Add all the numbers. 8, 10, 12, 18, 22, 26 8+10+12+18+22+26 = 96

How to Find the Mean of a Group of Numbers Step 2 – Divide the sum by the number of addends. 8, 10, 12, 18, 22, 26 8+10+12+18+22+26 = 96 How many addends are there?

How to Find the Mean of a Group of Numbers Step 2 – Divide the sum by the number of addends. 1 6 6) 96 # of addends sum 6 3 6 3 6

How to Find the Mean of a Group of Numbers The mean or average of these numbers is 16. 8, 10, 12, 18, 22, 26

Ex1 :What is the mean of these numbers? 7, 10, 15 10.6

Ex 2: What is the mean of these numbers? 2, 9, 14, 27 13

Definition Median is in the Middle

How to Find the Median in a Group of Numbers Step 1 – Arrange the numbers in order from least to greatest. 21, 18, 24, 19, 27 18, 19, 21, 24, 27

How to Find the Median in a Group of Numbers Step 2 – Find the middle number. 21, 18, 24, 19, 27 18, 19, 21, 24, 27

How to Find the Median in a Group of Numbers Step 2 – Find the middle number. 18, 19, 21, 24, 27 This is your median number.

How to Find the Median in a Group of Numbers Step 3 – If there are two middle numbers, find the mean of these two numbers. 18, 19, 21, 25, 27, 28

How to Find the Median in a Group of Numbers Step 3 – If there are two middle numbers, find the mean of these two numbers. 46 21+ 25 = median 23 2) 46

Ex 4: What is the median of these numbers? 16, 10, 7 7, 10, 16 10

Ex 6: What is the median of these numbers? 31, 7, 2, 12, 14, 19 2, 7, 12, 14, 19, 31 13 2) 12 + 14 = 26 26

Mode is the most Popular Definition Mode is the most Popular

How to Find the Mode in a Group of Numbers Step 1 – Arrange the numbers in order from least to greatest. 21, 18, 24, 19, 18 18, 18, 19, 21, 24

How to Find the Mode in a Group of Numbers Step 2 – Find the number that is repeated the most. 21, 18, 24, 19, 18 18, 18, 19, 21, 24

Ex 7: number is the mode? 29, 8, 4, 8, 19 4, 8, 8, 19, 29 8

Ex 8: Which number is the mode? 1, 2, 2, 9, 9, 4, 9, 10 1, 2, 2, 4, 9, 9, 9, 10 9

What is an Outlier? A data item that is far apart from the rest of the data items Which will an outlier affect the most: the mean, median or mode? (Hint: Think of class test scores Sometimes you can throw out the outlier to find a more accurate mean

You need a mean test score of 90 points You need a mean test score of 90 points. So far, you have taken 5 tests: 94, 84, 90, 88, and 91. What is the minimum score you need on your next test to get an A.

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